1. Field of Invention
The present invention relates to a surface texturization method.
2. Description of Related Art
Solar energy is a very promising clean energy. A solar cell which can directly convert solar light into electricity has been the focus recently. One of the major requirements for obtaining a high-efficiency solar cell is to enhance the absorption of solar light. All high-efficiency crystalline silicon solar cells up to date are textured on the front surface to reduce the reflection losses and to improve the light-trapping properties.
In the light-absorption mechanism, with a multi-crystalline silicon solar cell as an example, the conventional process includes performing a wet etching process to macro-texturize the surface to a micron scale and then depositing an anti-reflection coating for enhancing the absorption rate of solar light. However, the average reflectivity of such micron-scale textured structure is usually more than 10% in the wavelength range from 300 nm to 900 nm, i.e. the spectra region of strong Si absorption.
Currently, when the surface textured structure has a dimension close to the wavelength of incident solar light (i.e. the surface is a nano-scale textured structure), it has been proved to be quite efficient in capturing the incident light having a wavelength less than 1.1 um. However, the method of forming such nano-scale surface textured structure requires performing a more expensive and time-consuming vacuum sputtering, a complicated electroless plating metal deposition or a copolymerization reaction, so as to form a heavy burden in the fabrication cost.
Accordingly, how to fabricate a nano-scale surface textured structure quickly at low cost so as to effectively enhance the efficiency of the solar cell has become one of the main topics in the industry.